It is known that synthetic materials can be protected against microbial influences by incorporating antimicrobially active substances in these materials. In particular, it is known to incorporate phenoxyarsines, for example 10,10'-oxybis-phenoxyarsine, as an antimicrobial agent to protect these synthetic materials. This is generally carried out by treating the plasticizer used in the manufacture of these synthetic materials, for example in the manufacture of vinyl resins such as polyvinyl chloride, with a solution of the phenoxyarsine. Various solvents for the phenoxyarsine have been proposed for this purpose. For example, phenols and aliphatic alcohols such as nonylphenol, as well as certain phosphites and phosphonates such as tris(dipropyleneglycyl)phosphite are disclosed in U.S. Pat. No. 3,288,674. In various respects these solvents have disadvantages which are to some extent considerable, namely:
--low dissolving capacity at room temperature, PA0 --high viscosity and difficulties associated therewith during the processing, PA0 --troublesome odors, PA0 --low boiling points, PA0 --unsatisfactory miscibility with the plasticizers usually used in the plastics industry, and PA0 --unfavorable toxicological properties.
It has been found that it is possible to overcome the above-noted disadvantages by using certain organic solvents in combination with phenoxyarsine antimicrobial agents.